Apparatus for cleaning a hydraulic fluid

Abstract

An apparatus for cleaning hydraulic fluid includes a centrifugal fluid-spinning disk arranged in a housing, of which an upper portion forms a vapor chamber and a lower portion forms a fluid collecting basin. A vacuum pump is connected to the housing through an oil mist separator, such that water vapor is vacuumed away and hydraulic fluid collects in the oil mist separator to then be pumped away. The apparatus further includes preferably a single container that contains both the contaminated hydraulic fluid that is to be cleaned and the cleaned hydraulic fluid. A flexible inlet line and a flexible outlet line with respective hydraulic quick connectors are provided to connect the apparatus and particularly the oil container to a hydraulic system of an aircraft, for example. A high pressure pump connected to the outlet line pumps the cleaned hydraulic fluid into the aircraft hydraulic system and a pressure maintaining valve in the inlet line maintains the system pressure. The apparatus is embodied as a self-contained and self-sufficient mobile unit mounted on wheels. With this apparatus, the hydraulic fluid in the hydraulic system of an aircraft can be cleaned directly plane-side, and it is unnecessary to provide an exchange quantity of hydraulic fluid.

What is claimed is: 
     
       1. An apparatus for cleaning a contaminated hydraulic fluid in a hydraulic system to provide a cleaned hydraulic fluid, said apparatus comprising: a fluid container adapted to receive and contain the contaminated hydraulic fluid and the cleaned hydraulic fluid,   a flexible inlet line connected to said fluid container and having an inlet end adapted to be removably connected to the hydraulic system to flow the contaminated hydraulic fluid from the hydraulic system,   a flexible outlet line connected to said fluid container and having an outlet end adapted to be removably connected to the hydraulic system to flow the cleaned hydraulic fluid to the hydraulic system,   a centrifugal disk arrangement including a housing and at least one rotatable centrifugal disk arranged in said housing,   a contaminated fluid line connecting said fluid container with said centrifugal disk arrangement,   a vacuum pump connected to said housing of said centrifugal disk arrangement for vapor flow therefrom,   a hydraulic fluid mist separator interposed and connected between said housing of said centrifugal disk arrangement and said vacuum pump,   a hydraulic fluid pump with a suction port connected to said hydraulic fluid mist separator and a pressure port,   a cleaned fluid line connecting said pressure port of said hydraulic fluid pump with said fluid container,   a high pressure pump connected and interposed between said fluid container and said flexible outlet line and adapted to pump the cleaned hydraulic fluid through said flexible outlet line to the hydraulic system, and   a pressure maintaining valve connected and interposed between said flexible inlet line and said fluid container.   
     
     
       2. The apparatus according to claim 1, wherein said housing of said centrifugal disk arrangement includes a bottom portion forming a fluid collecting basin for cleaned hydraulic fluid, and further comprising a conduit connecting said fluid collecting basin to said pressure port of said hydraulic fluid pump. 
     
     
       3. The apparatus according to claim 1, further comprising first and second quick connectors respectively attached to said inlet end of said inlet line and said outlet end of said outlet line, and respectively adapted to be removably connected to the hydraulic system. 
     
     
       4. The apparatus according to claim 1, further comprising at least two wheels provided at a bottom of said apparatus, such that said apparatus is a mobile unit. 
     
     
       5. The apparatus according to claim 1, including a total of only one said fluid container that is adapted and connected in said apparatus so as to receive and contain both the contaminated hydraulic fluid and the cleaned hydraulic fluid without separation between the contaminated hydraulic fluid and the cleaned hydraulic fluid. 
     
     
       6. The apparatus according to claim 1, further comprising a hand-operable pump and a non-return valve connected in series with one another either between said fluid container and said inlet line or between said fluid container and said outlet line, wherein said hand operable pump is arranged and adapted to pump the hydraulic fluid into the hydraulic system, and further comprising a drain valve connected either between said fluid container and said inlet line or between said fluid container and said outlet line and adapted to drain the hydraulic fluid from the hydraulic system. 
     
     
       7. The apparatus according to claim 6, wherein said hand-operable pump and said non-return valve connected in series with one another, and said drain valve, are respectively connected in parallel with and bridging across said pressure maintaining valve. 
     
     
       8. The apparatus according to claim 1, further comprising an air inlet, an air filter, and a diaphragm arranged in series with one another and connected to said housing of said centrifugal disk arrangement. 
     
     
       9. The apparatus according to claim 1, wherein said vacuum pump is adapted to create in said housing a vacuum which acts to convey the contaminated hydraulic fluid through the contaminated fluid line into the centrifugal disk arrangement. 
     
     
       10. The apparatus according to claim 1, further comprising a single common drive motor operatively connected for drive transmission to said vacuum pump and to said hydraulic fluid pump. 
     
     
       11. The apparatus according to claim 1, further comprising at least one operating selection input element, at least one operating status indicator, and a base including at least two wheels,   wherein said fluid container, said inlet line, said outlet line, said centrifugal disk arrangement, said contaminated fluid line, said vacuum pump, said hydraulic fluid mist separator, said hydraulic fluid pump, said cleaned fluid line, said high pressure pump, and said pressure maintaining valve are mounted on said base,   such that said apparatus is a self-contained and self-sufficient mobile unit.   
     
     
       12. The apparatus according to claim 1, wherein said housing of said centrifugal disk arrangement includes a bottom portion forming a fluid collecting basin for cleaned hydraulic fluid,   further comprising a conduit connecting said fluid collecting basin to said pressure port of said hydraulic fluid pump,   further comprising first and second quick connectors respectively attached to said inlet end of said inlet line and said outlet end of said outlet line, and respectively adapted to be removably connected to the hydraulic system, and   further comprising at least two wheels provided at a bottom of said apparatus, such that said apparatus is a mobile unit.   
     
     
       13. The apparatus according to claim 1, wherein said contaminated fluid line is connected to a first end of said fluid container, said flexible inlet line is connected to said contaminated fluid line and is thereby connected to said first end of said fluid container, said cleaned fluid line is connected to a second end of said fluid container opposite said first end, and said flexible outlet line is connected to said cleaned fluid line and is thereby connected to said second end of said fluid container. 
     
     
       14. The apparatus according to claim 1, wherein said hydraulic fluid pump and said high pressure pump are respectively configured and adapted so that said hydraulic fluid pump delivers a higher fluid flow rate than said high pressure pump. 
     
     
       15. The apparatus according to claim 1, further comprising a wire mesh screen interposed in said contaminated fluid line between said fluid container and said centrifugal disk arrangement, a particle filter interposed in said cleaned fluid line, and an outlet fluid filter interposed between said fluid container and said outlet end of said outlet line. 
     
     
       16. The apparatus according to claim 1, further comprising a vacuum gauge interposed between said vacuum pump and said housing of said centrifugal disk arrangement, a vacuum manometer interposed in said contaminated fluid line, an inlet thermometer interposed in said contaminated fluid line, a supply pressure gauge interposed between said high pressure pump and said outlet end of said outlet line, and a return pressure gauge interposed between said inlet end of said inlet line and said pressure maintaining valve. 
     
     
       17. An apparatus for cleaning a hydraulic fluid of a hydraulic system, said apparatus comprising: a fluid container adapted to receive and contain a quantity of the hydraulic fluid,   fluid cleaning means for removing contaminants from the hydraulic fluid,   a first conduit connecting said fluid container to said fluid cleaning means,   a second conduit connecting said fluid cleaning means to said fluid container,   pump means interposed in said first conduit or in said second conduit and adapted to convey the hydraulic fluid in sequence from the fluid container, through the first conduit, through the fluid cleaning means, through the second conduit and into the fluid container,   an outlet line connected to said second conduit and having an outlet end adapted to be removably connected to the hydraulic system,   an inlet line connected to said first conduit and having an inlet end adapted to be removably connected to the hydraulic system,   a high pressure pump interposed in said outlet line and adapted to pump the hydraulic fluid from said second conduit, through said outlet line, through said outlet end, and into the hydraulic system, and   a pressure maintaining valve interposed in said inlet line and adapted to selectively restrict a flow of the hydraulic fluid through said inlet line to maintain a pressure in the hydraulic system.   
     
     
       18. The apparatus according to claim 17, wherein said fluid cleaning means comprise first means for removing volatile contaminants from the hydraulic fluid and second means for removing particulate contaminants from the hydraulic fluid,   said pump means comprise a vacuum pump connected to a vapor chamber of said first means and a hydraulic fluid circulation pump interposed in said second conduit, and   the apparatus is a self-contained, self-sufficiently operable mobile unit.   
     
     
       19. A method of cleaning a hydraulic fluid of a hydraulic system using an apparatus including a fluid container, a contaminant removal device, and a circulation pump connected in series with said fluid container and said contaminant removal device to form a circulation loop, a high pressure pump in an outlet line branching off from said circulation loop on an upstream side of said fluid container, and a pressure regulating valve in an inlet line branching off from said circulation loop on a downstream side of said fluid container, said method comprising the following steps: (a) connecting said inlet line to a first port of said hydraulic system, and connecting said outlet line to a second port of said hydraulic system;   (b) after said step (a) and while said inlet line and said outlet line are respectively connected to said first and second ports of said hydraulic system, operating said circulation pump to circulate said hydraulic fluid around said circulation loop from said fluid container through said contaminant removal device and back into said fluid container; and   (c) during said step (b), operating said high pressure pump to pressurize said hydraulic fluid to a hydraulic system pressure and pump said hydraulic fluid through said outlet line, into said second port, into and through said hydraulic system, out of said second port and through said inlet line at said hydraulic system pressure, wherein said pressure regulating valve maintains said hydraulic system pressure at a pressure level higher than a cleaning apparatus pressure present within said circulation loop.   
     
     
       20. The method according to claim 19, wherein said step of circulating hydraulic fluid around said circulation loop comprises circulating contaminated hydraulic fluid from said fluid container through said contaminant removal device so as to clean said contaminated hydraulic fluid to provide cleaned hydraulic fluid, and then circulating said cleaned hydraulic fluid back into said fluid container to form a partially-contaminated mixed hydraulic fluid therein, so that a degree of contamination of said partially-contaminated mixed hydraulic fluid is continuously reduced while carrying out said step of circulating hydraulic fluid around said circulation loop,   wherein said pressurizing and pumping hydraulic fluid in said step (c) comprises pumping said cleaned hydraulic fluid into and through said hydraulic system, wherein said hydraulic system pressure is at least about equal to a normal operating pressure of said hydraulic system, and returning contaminated hydraulic fluid from said hydraulic system into said inlet line, and   wherein said hydraulic system includes hydraulically actuatable components selected from hydraulic cylinders and hydraulic motors, and said method further comprises operating said hydraulically actuatable components during said step (c).